One New Aftermarket Replacement Fits Ford Complete Oil Pump Assembly Roto type, hex drive, 100 psi. For 144 or 172 CID diesel engines. Tractor series: 501, 601, 701, 801, 901, 2000, 4000, including HD industrial (1958-1964). Will retrofit 134 or 172 CID gas engine if necessary conversion parts have been installed when changing form gear type to roto type pumpPart Number: D1NL6600A, C3NN6621B